microRNA-128-3p overexpression inhibits breast cancer stem cell characteristics through suppression of Wnt signalling pathway by down-regulating NEK2

Emerging evidence has reported that dysregulation of microRNAs (miRNAs) participated in the development of diverse types of cancers. Our initial microarray-based analysis identified differentially expressed NEK2 related to breast cancer and predicted the regulatory microRNA-128-3p (miR-128-3p). Herein, this study aimed to characterize the tumour-suppressive role of miR-128-3p in regulating the biological characteristics of breast cancer stem cells (BCSCs). CD44(& xff0b;)CD24(-/low)cells were selected for subsequent experiments. After verification of the target relationship between miR-128-3p and NEK2, the relationship among miR-128-3p, NEK2 and BCSCs was further investigated with the involvement of the Wnt signalling pathway. The regulatory effects of miR-128-3p on proliferation, migration, invasion and self-renewal in vitro as well as tumorigenicity in vivo of BCSCs were examined via gain- and loss-of-function approaches. Highly expressed NEK2 was found in breast cancer based on GSE61304 expression profile. Breast cancer stem cells and breast cancer cells showed a down-regulation of miR-128-3p. Overexpression of miR-128-3p was found to inhibit proliferation, migration, invasion, self-renewal in vitro and tumorigenicity in vivo of BCSCs, which was further validated to be achieved through inhibition of Wnt signalling pathway by down-regulating NEK2. In summary, this study indicates that miR-128-3p inhibits the stem-like cell features of BCSCs via inhibition of the Wnt signalling pathway by down-regulating NEK2, which provides a new target for breast cancer treatment.